In the software/hardware engineering model-driven design methodology, preservation of real-time system properties can be guaranteed in the model synthesis up to a small time-deviation. Therefore, this methodology is well suited for the design and implementation of control systems in which execution times of actions are small; thus the time-deviations obtained are small. However, in systems containing time-intensive computations, the time-deviations become large and, consequently, the real-time properties are much weakened. This chapter proposes an approach for obtaining stronger preservation of the observable properties of the system by abstracting from its internal unobservable actions. In this way, a unified way of analysis and synthesis of a larger area of real-time applications can be obtained, which enables designers to achieve predictability in the design of many systems.